Implement committed physical memory stats for Linux.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 0515019630ad1d7e69f0f3b788072b50b090681c..fce16cebe31a590e279a8284d4863e1c8545b9f7 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -211,6 +211,20 @@ intptr_t Heap::CommittedMemory() {
       lo_space_->Size();
 }
 
+
+size_t Heap::CommittedPhysicalMemory() {

[Vyacheslav Egorov (Google), 2012/09/21 14:29:07]

This function might still return a number that is not accurate. Because when you
iterate over spaces to discover V8 Pages you touch memory and thus affect its
state. You might also end up asking OS to "unswap" OS-pages (ones that back
V8-Page headers that you access) that might have been swapped out and thus end
up with a bigger RSS than RSS before you called this function.

Also consider the following case:

1) you compute CommittedPhysicalMemory for new space
2) start computing CommittedPhysicalMemory, touch some swapped pages -> OS
un-swap's them and swaps pages backing new space this makes results computed for
new space obsolete.

+  if (!HasBeenSetUp()) return 0;
+
+  return new_space_.CommittedPhysicalMemory() +
+      old_pointer_space_->CommittedPhysicalMemory() +
+      old_data_space_->CommittedPhysicalMemory() +
+      code_space_->CommittedPhysicalMemory() +
+      map_space_->CommittedPhysicalMemory() +
+      cell_space_->CommittedPhysicalMemory() +
+      lo_space_->CommittedPhysicalMemory();
+}
+
+
 intptr_t Heap::CommittedMemoryExecutable() {
   if (!HasBeenSetUp()) return 0;